Letter to the Editor

Discovery of a nova super-remnant surrounding the recurrent nova LMCN 1971-08a in the Large Magellanic Cloud

¹ Dr. Karl Remeis Observatory, Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Sternwartstraße 7, 96049 Bamberg, Germany
² Astrophysics Research Institute, Liverpool John Moores University, Liverpool L3 5RF, UK
³ NSF’s NOIRLab/CTIO, Casilla 603, La Serena 1700000, Chile
⁴ School of Science, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
⁵ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
⁶ Eureka Scientific, Inc., 2452 Delmer Street, Suite 100, Oakland, CA 94602-3017, USA

^⋆ Corresponding author: michael.healy-kalesh@fau.de, M.W.HealyKalesh@ljmu.ac.uk

Received: 30 July 2025
Accepted: 16 September 2025

Abstract

A nova super-remnant (NSR) is a greatly-extended structure grown by repeated nova eruptions sweeping the surrounding material away from a nova into a dense outer shell and are predicted to form around all novae. To date, four NSRs are known, with three located in the Galaxy and one residing in M31. Here we present the discovery of the first NSR in the Large Magellanic Cloud and only the second extragalactic nova shell identified, hosted by the recurrent nova LMCN 1971-08a. The structure is coincident with the nova, has a circular morphology, and is visible in narrowband Hα and [S II] filters but is very faint in [O III] , as expected. H I data also potentially reveal the existence of a coincident structure. Further, with a diameter of ∼200 pc, this NSR is the largest example yet found, with models indicating an ∼4130 M_⊙ shell expanding at ∼20 km s⁻¹ into the surrounding medium and an age of ∼2.4 Myr. The existence of the NSR also suggests that LMCN 1971-08a may have a much shorter recurrence period than currently presumed.